You’re in a poker tournament (no-limit Texas Hold ’em, what else?) with a healthy chip stack. Some players are fairly short-stacked and people are getting knocked out left and right. The one player at your table with more chips than you raises under-the-gun from 400 to 2500. You look down and see KK. You posture a bit, pretending to struggle to decide what to do, and push all-in with your 20k or so chips. The dude calls and flips over AK off-suit. You know you’re the favorite to win. You might even know that you have almost exactly a 70% chance of winning. The board doesn’t give him an ace, a straight, or a flush, and he says, “you’re lucky that ace didn’t come up!” But you’re not lucky. The most likely outcome is exactly what occurred.

You’re at a dark, loud, and crowded bar full of drunk people and bump into a dude. Hard. He glares into your face and shouts, “you’re lucky I’m on probation!” Of course, if you’re the type of person who likes to get into fights and don’t feel too threatened by the convict or the prospect of being forcefully removed and possibly 86’ed from the bar, this would be the prefect time to kick some ass. If he fights back he might just go to prison. Alternatively, you could end up in jail, the hospital, or worse, but probably not. If you’re more risk averse you could simply say, “you’re lucky I’m not a grizzly bear!” He could trump you by saying, “you’re lucky I’m not Godzilla!”, but he probably won’t.

The whole “you’re lucky!” thing is childish threatening language intended to intimidate or belittle the “lucky” person. I think it’s a good idea to escalate the dialogue to the absurd:

You’re lucky I can’t breathe fire!

You’re lucky I suck at poker!

You’re lucky you’re not made of cheese! (then people would eat you)

You’re lucky it’s not 300 degrees in here!

You’re lucky there’s gravity!

You’re lucky you’re a white male born in the United States! (wait, people actually use that and don’t consider it absurd at all)